1 /* IP tables module for matching the value of the TTL
3 * ipt_ttl.c,v 1.5 2000/11/13 11:16:08 laforge Exp
5 * (C) 2000,2001 by Harald Welte <laforge@netfilter.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
15 #include <linux/netfilter_ipv4/ipt_ttl.h>
16 #include <linux/netfilter_ipv4/ip_tables.h>
18 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
19 MODULE_DESCRIPTION("IP tables TTL matching module");
20 MODULE_LICENSE("GPL");
22 static int match(const struct sk_buff
*skb
,
23 const struct net_device
*in
, const struct net_device
*out
,
24 const struct xt_match
*match
, const void *matchinfo
,
25 int offset
, unsigned int protoff
, int *hotdrop
)
27 const struct ipt_ttl_info
*info
= matchinfo
;
31 return (skb
->nh
.iph
->ttl
== info
->ttl
);
34 return (!(skb
->nh
.iph
->ttl
== info
->ttl
));
37 return (skb
->nh
.iph
->ttl
< info
->ttl
);
40 return (skb
->nh
.iph
->ttl
> info
->ttl
);
43 printk(KERN_WARNING
"ipt_ttl: unknown mode %d\n",
51 static struct ipt_match ttl_match
= {
54 .matchsize
= sizeof(struct ipt_ttl_info
),
58 static int __init
ipt_ttl_init(void)
60 return ipt_register_match(&ttl_match
);
63 static void __exit
ipt_ttl_fini(void)
65 ipt_unregister_match(&ttl_match
);
69 module_init(ipt_ttl_init
);
70 module_exit(ipt_ttl_fini
);